Protein-carbohydrate interactions are now recognized to be important mediators of cell communication. In the last decade many novel carbohydrate binding receptors have been described, several of which have been documented to play critical roles in cell trafficking and cell signaling. Despite these advances, the rate at which new information has been generated has been slow, and the biological roles of most mammalian carbohydrate binding proteins are poorly understood. While the importance of this field has attracted many outstanding laboratories, a major barrier to progress has been the complexity of the carbohydrates themselves and the analytical and synthetic challenges they pose. Exploring the functions of carbohydrate binding proteins requires the standard range of tools afforded by molecular and cell biology and models of genetic deficiencies, but in addition requires access to expertise in state of the art structure analysis and carbohydrate synthesis. Although the technology for analysis of carbohydrate structure and chemo-enzymatic synthesis of carbohydrates exists, it is not accessible to the general scientific community, and no laboratory has the breadth and depth of expertise to efficiently to explore the functions of carbohydrate binding proteins on a broad scale. The overarching goal of this project is to define the biochemical mechanisms by which protein-carbohydrate interactions mediate cellular events. The project brings together a multidisciplinary group of participating investigators that have a common goal of elucidating the roles of carbohydrate binding proteins in cell communication. Their combined expertise, aided by core resources that are currently unavailable, will dramatically accelerate progress in this emerging frontier.